The present invention relates to a triazine type monomer, and more particularly, to a 1,3,5-triazine type monomer expressed in the following formula (I) characterized by having at least one amine group and at least two sulfur atoms. The triazine monomers can be used in manufacturing transparent optical resin having excellent refractive index, surface hardness and light transparency as well as an improved workability and the ability to control a wide range of refractive index by adjusting composition by the monomer itself at room temperature or by polymerizing the monomer with a comonomer in the presence of an organic solvent or an initiator. 
Plastic transparent optical materials have been welcomed as matrices for manufacturing optical lenses, optical filters and transparent panels because they are light-weighted, less fragile and also more easily dyeable as compared to inorganic materials. In particular, the importance of developing plastics having high surface hardness and high refractive index has been much emphasized lately since the massive introduction of diethylene glycol biscarbonate allyl(CR-39) compounds in production of optical lens. However, CR-39 has a relatively low refractive index of below 1.50 even after curing process and thus the central region of the lens to be manufactured has to be thick in case of a convex lens while the periphery has to be thick in a concave lens thus resulting in production of heavy lenses.
Many lines of studies to develop monomers with high refractive index have been initiated since 1986. Various types of monomers including an alkyl- and meta-alkyl group were developed in 1990s, thus improving the refractive index of lenses to some extent. Nevertheless, the refractive index of those monomers were nb20: 1.526-1.519 and the refractive index of the resulting lenses produced accordingly was approximately nD25: 1.549. Therefore, the development of monomers having refractive index of higher than 1.55 still remains as a long-felt need.
Monomers having high refractive index can shorten the focal distance of given lenses and thus produce thin lenses; hence, they can be widely used in manufacturing optical lenses, transparent panels, optical heads and other light-weighted optical products. Polycarbonates, being a transparent optical resin, have rather high refractive index of 1.59, however, they have a few drawbacks that they are deficient in optical homogeneity and have poor anti-solvent and abrasion resistance properties thus not being suitable for manufacturing optical products requiring high transparency and high surface hardness.
To resolve the above problems, compounds with high refractive index containing an aromatic ring, thiol or a halogen group in the molecule have been developed. Recently, polyurethanes were developed to increase both the refractive index and the Abbe number. However, these polyurethanes are also not recommended because they would impede hard coating and multi-coating and also result in relatively low lens production yield due to their poor thermal stability and low surface hardness.
Japanese Patent Publication 11-263811 discloses a method of preparing a curing composition with good workability to give a cured product, consisting of a cyanuric acid or an isocyanuric acid, with excellent optical properties and impact resistance. However, the cured product has refractive index of about 1.575, which is lower than the refractive index of lenses manufactured using polyurethanes. Therefore the development of monomers with excellent thermal stability, surface hardness and high refractive index as well as processability with other monomers is still highly required.
The inventors of the present invention developed a method to prepare a triazine-containing monomer as expressed in the formula (I) with refractive index higher than 1.6 and the optical products manufactured from the monomer were shown to have excellent physical properties with respect to transparency, refractive index, surface hardness and thermal stability. Therefore, the object of this invention is to provide a monomer and a composition containing this monomer which can be effectively used in optical industry such as manufacturing functional optical lenses, optical filters, optical displayers, optical discs or optical heads and other optical devices.
The present invention relates to a triazine type monomer, and more particularly, to a 1,3,5-triazine type monomer expressed in the following formula I characterized by having at least one amine group and at least two sulfur atoms 
wherein R1 is a secondary or a tertiary amine group selected from the group consisting of R4NHxe2x80x94, R4R5Nxe2x80x94 or 
R4 and R5 are independently C1-C22 alkyl or cycloalkyl; R6 is a C1-C15 alkylene or aromatic ring forming alkenes such as xe2x80x94CHxe2x95x90CHxe2x80x94CHxe2x95x90CHxe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94CH2xe2x80x94CHxe2x95x90CHxe2x80x94; R2 is C1-C22 linear alkylene, branched alkylene, or a 1,3-,1,4-benzene ring; R3 is R1 or xe2x80x94Sxe2x80x94( R2xe2x80x94S)nxe2x80x94X; X is an acryl-, methacryl or C2-C10 alkene group; and n is an integer of 1-10.
The method of preparing the above triazine type monomer used in the present comprises the following steps of:
(a) preparing triazine expressed in the following formula (IV) by reacting 2,4,6-trichloro-1,3,5-triazine with secondary- or tertiary amine;
(b) preparing triazine expressed in the following formula (V) by reacting said triazine obtained in the above step (a) with NaSH;
(c) preparing triazine expressed in the following formula (VI) by reacting said triazine obtained in the above step (b) with a thiol derivative expressed as Yxe2x80x94(R2xe2x80x94S)nxe2x80x94H in the presence of a mixed catalyst; and
(d) preparing triazine expressed in the above formula (I) by reacting said triazine obtained in the above step (c) with;
(i) a compound selected from a group consisting of acryloyl chloride, methacryloyl chloride, and allyl bromide in the presence of a mixed catalyst; or
(ii) propionyl chloride and then treat with a base, 
xe2x80x83wherein R1 is a secondary or a tertiary amine group selected from the group consisting of R4NHxe2x80x94, R4R5Nxe2x80x94 or 
xe2x80x83R4 and R5 are independents C1-C22 alkyl or cycloalkyl; R6 is C1-C15 alkylene or an aromatic ring forming alkenes such as xe2x80x94CHxe2x95x90CHxe2x80x94CHxe2x95x90CHxe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94CH2xe2x80x94CHxe2x95x90CHxe2x80x94; R7 is the same as R1 or Cl; R8 is the same as R1 or SH; R9 is the same as R1 or Sxe2x80x94(R2xe2x80x94S)nxe2x80x94H; R2 is C1-C22 linear alkylene, branched alkylene, or a 1,3-,1,4-benzene ring; R3 is R1 or xe2x80x94Sxe2x80x94( R2xe2x80x94S)nxe2x80x94X; X is an acryl-, methacryl or C2-C10 alkene group; n is an integer of 1-10; and Y is a leaving group selected from Cl, Br and OH. Thus obtained triazine monomers of the present invention can be used to manufacture transparent optical products via self-polymerization of these monomers or copolymerization in the presence of comonomer(s). The overall physical properties of the optical products such as refractive index can be adjusted by preparing the polymerizable resin composition so that it comprises 1-98 wt % of the monomer of the present invention; 1-98 wt % of either an aromatic radical polymerizable monomer or a comonomer with an unsaturated group; and 0.5-5 wt % of an initiator.
The methods of manufacturing of plastic products using the above composition can include various procedural methods such as thermosetting of the resin composition at 10-130xc2x0 C., radiation curing of the resin composition at 10-130xc2x0 C., or first radiation curing the resin composition at 10-130xc2x0 C. followed by thermo setting of the resin composition at 10-130xc2x0 C.
The present invention is explained in greater detail by means of the methods of manufacturing a triazine type monomer with high refractive index.
The novel triazine type monomers are manufactured by the reactions shown below, wherein polymerizable triazine type monomers with high refractive index expressed in the formula I are manufactured by the method comprising steps of substitution of at least one chloride groups in 1,3,5-triazine-chloride with an amine group, substitution of at least one of the remaining chloride groups in the 1,3,5-triazine-chloride with a thiol group and reacting with a thiol derivative, and introduction of an unsaturated group. 
In the above reactions, Y and Z represent a leaving group such as Cl, Br or OH, respectively.
1) Step 1: Reacting 2,4,6-trichloro-1,3,5-triazine with a Secondary or a Tertiary Amine
Chloro-1,3,5-triazine [formula (IV)] having at least one amine group is produced by reacting 2,4,6-trichloro-1,3,5-triazine[formula (II)] with amine[formula (III)] according to the method by Thurston et al. (J. T. Thurston, J. R. Dudley, D. W. Kaiser, I. Hechenbleikner, F. C. Scaefer, D. Holm-Hansen, J. Am. Chem. Soc., 1951, 73, 2981).
2) Step 2: Reacting with NaSH
Triazinethiol wherein a chloride is substituted with a thiol[formula (V)] is produced by reacting the Chloro-1,3,5-triazine [formula (IV)] having at least one amine group obtained in the above step 1 with NaSH according to the method by Kobunshi Ronbunshu [Kobunshi Ronbunshu (1999), 56(3), 159-165, Kim, Jae Jong; Oishi, Yoshiyuki; Hirahara, Hidetoshi; Mori, Kunio].
3) Step 3: Reacting with Yxe2x80x94(R2xe2x80x94S)nxe2x80x94H in the Presence of a Mixed Catalyst
A compound represented by the formula VI is produced when the formula V is reacted with Yxe2x80x94(R2xe2x80x94S)nxe2x80x94H. The solvent that can be used here is one or a mixture of more than two selected from the group consisting of toluene, benzene, dichloromethane and chloroform. The catalyst used here is one or a mixture of more than two selected from the group consisting of such as NaOH, KOH, tetrabutyl ammoniumchloride and benzenetriethyl ammoniumchloride (BTEAC) of quarternary ammonium salts. Reaction is performed at 30-120xc2x0 C., preferably 50-80xc2x0 C., and for 2-48 hrs, preferably for 4-16 hr.
4) Step 4: Reacting with a Compound Selected From the Group Consisting of Acryloyl Chloride, Methacryloyl Chloride and Allyl Bromide, or with Propionyl Chloride in the Presence of a Mixed Catalyst Followed by Base Treatment
There are two methods to produce the compound represented by the formula (I) by using the compound represented by the formula (VI).
The first method is to react the compound represented by the formula (VI) with a compound selected from the group consisting of acryloyl chloride, methacryloyl chloride and allyl bromide. The solvent used in the reaction is one or a mixture of more than two selected from the group consisting of toluene, benzene, dichloromethane and chloroform. The catalyst used here is one or a mixture of more than two of phase transfer catalyst selected from the group consisting of such as NaOH, KOH, tetrabutyl ammoniumchloride and benzenetriethyl ammoniumchloride (BTEAC) of quartenary ammonium salts. Reaction is performed at xe2x88x9210 to 80xc2x0 C., preferably 0-60xc2x0 C. Reaction is performed for 0.5-48 hr, preferably for 1-16 hr.
The second method is to react the compound represented by the formula (VI) with propionyl chloride followed by treatment with a base. The solvent used in the reaction is one or a mixture of more than two selected from the general organic solvent including dioxane, tetrahydrofuran and acetone. Reaction is initiated by adding propionyl chloride dropwise into the reactant containing the compound represented by the formula (VI) at xe2x88x925 to 50xc2x0 C., preferably 0-25xc2x0 C., and stirring the mixture for 10 min-5 hr, preferably 0.5-3 hr. To this reactant is added general amine such as triethylamine and is allowed to react at xe2x88x925 to 50xc2x0 C., preferably 0-25xc2x0 C., for 1-48 hr, preferably 5 min to 16 hr and finally transparent polymerizable monomer having refractive index of more than 1.6 is obtained.
The reaction of manufacturing the compound represented by the a formula (I) from the compound represented by the formula (V) can be proceeded continuously without necessitating a purification step. The above reaction, however, can be reinitiated after separation and purification of compounds obtained in each step, if higher purity is required. Thus obtained monomers of the present invention are recommended as optical materials for manufacturing optical products such as camera lenses and plastic lenses for glasses, which require excellent surface hardness, transparent, odorless and light-weighted properties.
Below are the preferred embodiments of each component of the resin composition according to the present invention.
The polymerizable resin composition of the present invention comprises 1-98 wt % of a monomer expressed in the formula (I); 1-98 wt % of either an aromatic radical polymerizable monomer or a comonomer with an unsaturated group; and 0.5-5 wt % of an initiator, and overall physical properties (e.g., refractive index) can be modified by adjusting the amount of the above-mentioned components within the range mentioned above.
The compound represented by the formula (1), which is included as a polymerizable monomer, has relatively high refractive index and enables to perform a radical polymerization by means of UV light or heat and thus becoming very useful in manufacturing transparent optical compositions with high refractive index.
The examples of preferred chemical structures of the formula (I) are as follows. 
The examples of the aromatic radical polymerizable monomers which can be used along with the compound represented by the formula (I) are:
Diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, butanediol dimethacrylate, hexamethylene dimethacrylate, bisohenol A dimethacrylate, 2,2-bis(4-methacryloyloxyethoxy-3,5-dibromophenyl)propane, 2,2-bis(4-methacryloyloxyethoxyphenyl)propane, 2,2-bis(4-methacryloyloxydiethoxyphenyl)propane, 2,2-bis(4-methacryloyloxytriethoxyphenyl)propane, 2,2-bis(4-methacryloyloxypentaethoxyphenyl)propane, bis-4-vinylbenzyl ether, bis-4-vinylbenzyl sulfide, 1,2-(p-vinylbenzyloxy)ethane, 1,2-(p-vinylbenzylthio)ethane, bis-(p-vinylbenzyloxyethyl)sulfide.
Other usable radical polymerizable monomers are disclosed in Japanese Patent Publication Nos. 4-11613, 4-161411, 5-188201, 6-123855, 6-202049, 6-16723, and below are the selected examples of their structures. 
In addition to the monomers shown in the above, one or more comonomers such as NK55[a mixed composition of aromatic dimethacrylate, xcex1-methylstyrene, tetra(ethylene glycol) dimethacrylate, isopropenyl benzene, and tribromophenyl acrylate], CR39(bisallylethylene glycol carbonate) (Aldrich Chemical Co., Ltd., USA), xcex1-methylstyrene, styrene, polyethyleneoxymethacrylate, polyethyleneoxyacrylate, polyethyleneoxydiacrylate, polyethyleneoxytriacrylate, and other comonomers with an unsaturated group can be added for the copolymerization with formula (I).
Initiators, after decomposition into a radical by either heat or UV irradiation, can initiate polymerization of triazine monomers and can be selected one or more from the group consisting of 2,2xe2x80x2-azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), diisopropyl peroxydicarbonate (IPP), tertiary butyl hydroperoxide (TBPO), t-butyl peroxy 2-ethylhexanoate and other thermo-setting initiators; or one or mixture of initiators selected from the group consisting of Irgacure (1-hydrocyclohexyl phenylketone, benzophenone, 2-hydroxy-1-[4-(hydroxyethoxy)phenyl]-2-methy-propanone, 2,2-dimethoxy-2-phenylacetophenone, fluorinated diaryltitanocene (product of Ciba-Geigy Co., Ltd., Switzerland) and known photo initiators such as 2,2-bis(hydroxymethyl)propionic acid (DPMA).
Further, aliphatic unsaturated compounds and organic solvents can be added in addition to the above-mentioned active components for the purpose of adjusting film thickness as well as viscosity. Additives that delay the polymerization, polymerization catalysts, UV absorbents and anti-coloring agents for enhancing abrasion resistance property can be also used, and stirring, filtration and defoaming processes can be also introduced during manufacturing of compositions.
The resins manufactured using the resin composition according to the present invention by means of photo polymerization or thermal polymerization are characterized by having excellent transparency, surface hardness, abrasion resistance and refractive index. Therefore, the resin composition of the present invention can be used in manufacturing transparent optical products such as functional optical lenses, filters, imaging, display elements or optical integrated elements, holograms, optical discs, optical recording materials, optical pickup parts and the like.
The resin composition of the present invention can be coated on glass plates, ITO, silicon wafer and other support membranes. The resin composition can be molded by radiation curing or thermosetting by putting it into molds made of various materials and it is recommended to introduce the resin composition into molds or gaskets by the pressure of air or nitrogen gas. Thermosetting is usually proceeded for 3-48 hr depending the amount of resin composition and the initiator. When using benzoylperoxide (BPO) as initiators, for example, the thermosetting is performed at xe2x88x9220-120xc2x0 C. and it is preferred to cure for 30 sec xe2x88x922 hr using UV lamp, UV curing equipment and a Zenon lamp. In case of photo polymerization of a composition comprising 88 g of a monomer represented by the formula (I), 8 g of a compound represented by the Structure 13, 2 g of Irgacure 184 photo initiator and 8 g of tetrahydrofuran solvent, a film with 3 xcexcm of thickness, 1.65 of refractive index and 3H of pencil hardness is formed when cured by UV curing equipment for 5 min at room temperature.
The resin composition of the present invention can be used in manufacturing transparent optical products such as plastic lenses, films, light transparent films and image forming materials.
First, plastic lenses can be manufactured by inserting resin composition into a mold followed by thermal curing. Here, the temperatures are changed stepwise during the heat curing process as follows: the temperature is kept at between room temperature and 70xc2x0 C. for 30-360 min for the initiation of decomposition of an initiator and prepolymerization, 70-80xc2x0 C. for 110-180 min, 85-95xc2x0 C. for 110-130 min, 110-130xc2x0 C. for 30-240 min and is then allowed to be naturally cooled down.
Films can be manufactured by inserting resin composition into a glass mold followed by photo curing by UV irradiation for 30 sec to 2 hr. Also, the light transparent films can be manufactured by coating on a plate such as silicon wafer followed by UV irradiation for 30 sec to 2 hr. The radiant curing of these light transparent films and thin films can be performed by using a UV lamp, a UV curing equipment or a Zenon lamp.
Images are to record mask images on a plate, wherein resin composition is coated on a silicon wafer, a transparent plastic plate, an ITO or a glass plate and then the images are recorded by UV irradiation. Then, the mask is removed, dipped into a solvent and then dried to reveal the embossing of the mask images (recorded part). The embossing part of the masking images can be stable for more than a year. The examples of the above plates include silicon wafers, transparent plates, ITO and glass.
Hereunder is given a detailed description of the present invention using the following examples, however, it should not be construed as limiting the scope of the present invention.
The following Preparation Examples 1 and 2 show only a part of the methods to synthesize the starting materials used to prepare starting materials of the present invention and other starting materials can be easily prepared by using the known methods or by purchasing the commercial products.